Genetics might be key to the anti-cancer benefits of drugs like aspirin or ibuprofen, study finds

TUESDAY, March 17, 2015 (HealthDay News) -- Prior research has suggested that regular use of a certain class of painkillers might lower colon cancer risk, but a new study finds that a person's genetics may also play a big role.

Regular, long-term use of nonprescription painkillers called nonsteroidal anti-inflammatory drugs (NSAIDs) -- drugs that include aspirin, naproxen (Aleve) and ibuprofen (Motrin, Advil) -- are associated with an overall lower risk of colon cancer.

But who benefits? In the study, a team led by Dr. Andrew Chan, of Massachusetts General Hospital in Boston, and Li Hsu, of the Fred Hutchinson Cancer Research Center in Seattle, looked at studies conducted between 1976 and 2011. The studies included more than 19,000 people from the United States, Canada, Australia and Germany.

Overall, the risk of colon cancer was lower for people who were regular users of aspirin and/or other NSAIDs, compared to those who weren't regular users of the drugs, the investigators found.

But certain people gained more or less. For example, there was no benefit for the 9 percent of people with variations in a certain gene called rs16973225, the researchers found. On the other hand, regular aspirin/NSAID use actually seemed to boost the odds of colon cancer among the 4 percent of people with two rare variations of a gene called rs2965667, the team said.

According to Chan and Hsu, this type of research could lead to the use of genetic tests to identify people who would get the greatest cancer-preventing benefit from regular use of aspirin/NSAIDs.

The study appears in the March 17 issue of the Journal of the American Medical Association.

"In the not-too-distant future it will be possible to affordably and efficiently conduct genetic testing in healthy individuals to more accurately define benefits and risks of interventions intended to decrease risk of disease," Dr. Richard Wender, of the American Cancer Society, wrote in an accompanying editorial.

Another gastroenterology expert agreed.

Dr. Arun Swaminath is director of the Inflammatory Bowel Disease Program at Lenox Hill Hospital in New York City. He said the new study is another step "toward the age of personalized medicine."

"Over the past 10 years, our ability to study the whole human genome with enough sophistication and at a manageable price point has improved significantly," Swaminath said. "We are much closer to being able to make decisions at an individual level rather than at a population level," he added.

"It's the difference between being told 'Aspirin can reduce the risk of developing colon cancer in the U.S. population by 30 percent, so you should try it,' to 'Taking aspirin, in your case, would be harmful because you have a genetic mutation that would actually raise the risk of developing colon cancer," Swaminath explained.

Wender stressed, however, that it will be vital for primary care doctors to understand genetic risk and to have informed discussions with patients about how to use this information.